Confessions of a Proton

by Michael S. Wisz

    It's humbling to admit, but a lot happened before you were born. During the universe's over 10 billion year life span, generations of stars have formed and died, life has sprung up on earth from a soup of organic molecules, the human species evolved, and thousands of generations of humans have spent time on the planet we call home. And then you came into the picture, your life a blink in the cosmic time frame.

    A proton does not experience conscious life as we know it, but if it could tell the story of its inanimate "life," there would be quite a tale to recount. Of course a proton cannot feel physical sensations or understand conditions around it, but imagining what it would say if it did have the biological senses is the basis for this "diary." Unlike the vastly long sequence of events that occurred before you came into existence, a mere 10 millionths of a second elapsed before the protons formed out of more fundamental particles called quarks. To follow the life of one of these protons from its birth to the present day takes us back to the beginnings of the universe, and leads us into the distant future.

    Ancestry of the proton: Ultimate Symmetry, quarks, and leptons...
Around 10 billion years ago, all the matter that's in the universe today, making up the galaxies, stars, planets, and people, was contained in a point the size of a proton. Suddenly, for reasons still unknown, this point started to expand. The very fabric of space and time started to push outward into the surrounding void, an expansion that continues still. As inhabitants of this point that we call the universe, we still cannot explain why the Big Bang happened, and perhaps never will.

    Physicists and astronomers call the first 10-43 seconds of the universe a simple, beautiful, and elegant place. All of the forces that we know of today (gravity, electro- magnetism, the strong and weak forces), were unified into one force that interacted with only one kind of particle. There were no whirling disks of stars and dust held together by gravity, much less neutrons, protons, and electrons as the building blocks of these great structures. The high temperatures and energetic collisions at this time surpass anything that can be reproduced in an earthly physics lab, falling in the realm of theory.

    A very short time later, when the universe was 10-35 seconds old, the ultimate symmetry of the universe was broken when the unified force divided into the strong, electroweak, and gravitational forces. Similarly, the single particle that existed in the "elegant" universe now took the form of leptons, weakly interacting particles like electrons, and quarks, the smallest building blocks making up protons and neutrons.

    The forces took their final form at 10-10 seconds. The electroweak divides into the electromagnetic and weak forces, complementing the already existing strong and gravitational forces. This marks the earliest time that present day particle accelerators can simulate the conditions of the universe. The proton's birth is imminent.

Birth of the proton...
    Only 10 millionths of a second have passed since the universe's birth, but the stage is already set for our proton. The universe, expanding quickly, cools off slightly in this short time, just enough for the quarks, with the help of the leptons, to "freeze" into the elementary particles, the protons and neutrons. The electrons also form from their predecessors, the leptons, but so far the present day constituents of atoms do not seem to want to get together. The protons and neutrons hook up to form nuclei at 3 minutes, but for now the universe is just too hot to allow any stable union between electrons and nuclei.

    In this early picture, a nucleus collides with an electron, seems to be stable, but then is abruptly knocked apart by another hot, energetic particle. For another 100,000 to one million years our proton lives a very violent, unpredictable life, jostled around, constantly being paired up with some electrons only to be rudely separated, until finally the universe has cooled enough to allow a successful marriage between the proton and its counterpart, the electron. For the first time, the proton becomes an integral part in a construction larger than itself, as the electromagnetic force keeps the proton and electron in a stable relationship necessary for all atoms to exist. Hydrogen is born!

The Diary:
    300 million years since creation: Times are more peaceful now. My first memories are of a crowded, violent place where I could hardly move in one direction without getting rudely jolted by another particle. There seemed to be no order or structure, and I wondered for a while if I had any purpose. Of course, things calmed down a bit and became less crowded to enable my stable partnership with the electron, but all this time of floating about aimlessly has given me no indication of what the electron and I can accomplish!

    500 million years since creation: As I fly through this strange place with my companion, the electron, I see some semblance of order around me. Other hydrogens seem to be getting together in large groups, attracted to each other by gravity, the dominant force around here. I seem to remember when I was solitary that another force had the upper hand, bringing me together with the electron. But then again I never did have a good sense of time.

    1 billion years since creation: Finally, I feel that my existence has a purpose. Recently I've noticed that the space around me has become more crowded, as more of my fellow hydrogens group together, drawn by this "gravity" force. I hope we are not going to revert back to that early, chaotic time of aimless bumping around!

    1.5 billion years since creation: This crowding together of hydrogens might have potential after all! Some sort of disk is emerging, an order that I haven't seen before, and the force between us gets stronger with time, drawing more hydrogens in. For the first time my motion is constrained, as I move in a sort of an orbit about the center of this huge collection of atoms, being pulled closer all the time. I am probably almost at the center of this big sphere, because I keep bumping into other hydrogens with quite a force, but thankfully not enough to break them apart from their electrons.

    1.6 billion years since creation: Something extraordinary happened - I have a purpose! As the collisions got more violent and the temperature kept rising, I knew that it was only a matter of time before either conditions calmed down or broke me apart from my electron. Well, instead, I have gained yet more companions! In an amazingly powerful collision with three other hydrogens, we somehow fused into a new structure called helium, followed by a burst of energy and a strange new phenomenon that I call "light." At the same time all the other hydrogens started undergoing the same transformation, inundating the space around us with this beautiful light, giving off energy in a chain reaction that has effectively "turned on" this proto-star. My companions, one other proton and two particles called neutrons, are held together by a different force than the one that holds us all together with our two orbiting electrons. For now, the excitement has died down as we move away from the core to a less active region, but that leaves me time to ponder our new creation.

    2 billion years since creation: Since "first light," I have been growing larger with companions as we fuse with others to feed this star's enormous need for energy. After each fusion, we move farther out from the center of the star, to the point where we now form a team of six protons, six neutrons, and six electrons. We have become carbon.

    2.1 billion years since creation: The view from the surface of this star we have lived in is impressive. Huge flares of glowing gases leap above the blue surface, only to be pulled back down by the force of gravity, but the more breathtaking sight is the one looking out into our universe. I feel somewhat humbled by the fact that I am just part of one of the many points of light called stars out there, one proton of one atom of one star. And the stars even take on different colors - some red, some orange, some yellow, and some blue, like ours. The universe seems to have grown into a much more interesting place than when I was born! I wish I could travel to those distant points, but I fear that my fate lies trapped by the inescapable bonds of gravity here.

    2.2 billion years since creation: This universe is definitely full of surprises! Let me recount the events of the past 100 million years: For a while we remained content on the surface, taking in the universe around us from our hot blue vantage point, until suddenly we felt a force pulling us and everyone around us back toward the center. The star was shrinking! As it used up the last of its nuclear fuel, gravity was winning over the nuclear fire that kept the star alive. Faster and faster the surface shrank as it pulled inward, causing pretty dense overcrowding among all the atoms. Would we be all be sucked into the star's core, torn apart forever, ending our existence? Had we served our purpose in giving life to this once dead mass?

    Incredibly, as suddenly as we had started shrinking, an equally unexpected force propelled us all outward into space with an explosion of such a magnitude that our home was torn apart. We traveled together at tremendous speed away from the once blue supergiant, looking back to see a tiny, dim core of spinning neutrons left over from the cataclysm. How many other protons can say they made it through a supernova?

    4 billion years since creation: The last 2 billion years have been very memorable. We've had the opportunity to travel through the universe, witnessing changes and structure that I never could have imagined! Besides us atoms grouping into stars, we have observed even the stars teaming up to form magnificent spirals, ellipses, and other strange shapes called galaxies. Some of these galaxies have extremely bright sources of energy at their centers, making our blue supergiant home of ages past seem insignificant. Right now we are traveling in the vast expanse between these islands, where we seldom ever meet with another atom. Are we destined to spend the rest of time watching from the side as the universe evolves, or is there some greater role for us to play?

    6 billion years since creation: After 4 billion years of lonely travel, we have finally passed into one of the islands of stars, a galaxy, and now seem to be right outside of a medium sized orange yellow star surrounded by a curious swirling disk of dust and gas. Our trajectory takes us right into this disk, where we start to form an even larger grouping with atoms of carbon and other unfamiliar atoms. It seems that we are not the only ones bringing some order to this once featureless disk, because many other small spheres of matter seem to be coming together as they orbit the brightening star. As more time passes, the disk has been transformed into a myriad of large and small bodies, gravitationally bound to this star. Together with our large group of atoms, we follow a predictable path, occasionally disrupted by collisions with other groups. The rate of these crashes slows down, however, and once again we have some time to appreciate the changes taking place around us.

    4.5 billion years ago: During the past 4 and a half billion years, we have once again observed an ordered system evolve out of a seemingly disorderly beginning. Is this a rule for the universe, or an exception in a universe that tends toward disorder? In our small corner of the cosmos, we see a star that was once peeking out through a cloud of dust in its infancy now shining bright and clear on nine distinct planets and countless smaller asteroids, of which we are one.

    65 million years ago: Our path has been altered a few times by intersections with random asteroids, but now we seem to be heading ever closer to a pale blue dot in the distance, the third planet of this yellow star. As our approach grows nearer, I can see irregular brown shapes amidst large blue areas spread across the surface of the body. Of all the sights I've seen, this planet seems unique.

    Our entry into the planet's atmosphere was exciting, spreading a heat wave through our asteroid as we rapidly plunged towards the surface below. During our descent I saw more details than ever - huge slabs of rock like us, jutting up from the ground, snaking paths of water cutting through the land, and even vast areas of green spreading in all directions. As our fireball descended, all my time traveling the universe in silence ended when I experienced the sensation of sound - I could hear the wind rushing furiously by! Right before the moment of impact, I thought I saw some kind of creatures moving about and heard their powerful roars, but these sights and sounds were immediately extinguished when we hit the ground in an unforgettable deafening blast of heat and light, setting our carbon atom free from the asteroid and back up into the thick atmosphere above.

    The light has gone. Everything is black. We fly above this planet, looking down on a world once lush with green, now transformed into a cold and dark place. The yellow star's light cannot shine through the shroud that we have created over the planet. I wonder what that creature was, and if it needs the light and warmth and green to survive?

    2 million years ago: I often ask myself why each stage of my life seems to me marked by a violent event, an explosion. Was this just another one in a series of many? These questions will have to wait, because the planet has brightened and the green has returned!

    We are flying above the surface with many different kind of atoms, especially these strange atoms that seem to be paired up. There is one kind with a pair of nuclei containing seven protons in each, called nitrogen, and another with eight protons in each, called oxygen. Even the occasional triple oxygen comes along! We seemed small in comparison, until one of these oxygen pairs approached us. After a relatively weak collision (we've been through nuclear fusion!), we ended up strangely sandwiched between these two oxygens. Initially I was repulsed and pushed away by the oxygen nuclei, but to my surprise those tiny electrons that I thought were useless actually hold this whole thing together, traveling back and forth from one end of the molecule to the other! Carbon dioxide is born.

    20 years ago: At long last we are making a return down to the surface, this time much more gradually than the first time, thankfully. The details that I remember seeing are all coming back to me now as we close in on the dense, damp, green region below. The forest is replete with leaves sucking in carbon dioxide molecules like us at an alarming rate. I have no idea what purpose this serves, but I know we're next.

    Our time in the plant gave me a totally different perspective on this universe. As we entered a large opening in the leaf, the plant soon took control of our path. Our two oxygens were torn off, and taken by the plant down a separate corridor from us, as we continued on to an unknown destination. We entered a larger chamber in which it seemed like thousands of other carbons were undergoing some massive assembly process, joining together in structures of six carbons or more. When our turn came, we banded together with five other carbons in a sort of ring-like formation, and were moved out of the room and into a more narrow region.

    The corridors kept becoming narrower and narrower as our "cellulose" molecule traveled through this complex new part of the universe. The tunnels were built by millions of square shaped objects that seemed to fit together perfectly, until our path came to a sudden and jagged end. It was here that a construction project was taking place, cellulose bonding with cellulose to encapsulate the cells making up the wall. These cells were spherically shaped and enclosed by a layer of special "machines" that seemed to regulate the materials passing into and out of the cell. Inside these cells we could see large green spheres moving about, along with a whole host of other unfamiliar molecules. What is it like in there? We wouldn't find out the answer yet. In order for the tunnels to be rigid and strong, the cells needed to be protected by an "armor." We were a part of this protective covering, the smallest building blocks that give the plant its shape.

    My time in the new universe of the plant was ended so soon after it began! All at once a huge section of the tunnel was ripped right down the middle, cut by some kind of giant blades from above and below. Soon all our surroundings were breaking up around us as some special molecules that had the power to break bonds bumped into us. From somewhere down a tunnel leading out of this cavern with the huge blades, a powerful animal voice vibrated everything around us. Our single cellulose was now heading down this tunnel, much larger than the one in the plant, surrounded on all sides by structures hundreds of times our size (one of them a beautiful red structure carrying oxygen atoms to various destinations). It was an amazing sight, this complex series of branching tunnels! Like in the plant, our course led us through ever shrinking tunnels until we came upon a familiar sight - a cell. However, this cell had no protective armor, and no strange green spheres inside.

    My wish of getting into a cell was granted. With the help of some machine that acted like a revolving door, our cellulose molecule passed easily through the membrane surrounding the cell, and a new world was opened to us. Inside the huge volume it seemed like each component had a job to do, a purpose. However, even more astounding was the network of proteins forming tubes that gave structure to this cell. These microtubules stretched far into the distance, where we could see an inner nucleus. And if the nucleus of a star is any indication, that is where it all happens. That's where I want to be!

    As we wandered around the cell, I noticed that there were molecular machines that bumped into random molecules, but docked with molecules of our type and carried them away to destinations unknown. The structures are more complex than anything I have seen before in this universe, with their helices and loops and strands folded up in such a compact form, perfectly fitting the molecules they carried. To our surprise, we were soon being transported to the nucleus by one of these remarkable structures. After our cellulose was broken up, leaving us a solitary carbon once again, we traversed the nuclear membrane.

    The long, twisted double helices, the basis of all life on earth, lay before us. As we watched, another machine, this one single stranded, moved along an unzipped portion of the double strand. As it "read" each rung of the ladder, it added a complementary section to itself, quickly growing in length, using as its building materials carbon, nitrogen, oxygen, hydrogen, and phosphorus.

    Our integration into life happened quickly. We were added to the growing single strand as part of one of the rungs of the ladder, one of the four bases that make up the genetic code. We are now part of the unique combination of these four bases that makes for the diversity of life on this planet. Life needs us just as the star needed us! I rather like our "purpose" here.

The continuing saga of the proton...
    Our proton spent the last 20 years in the cells of different animals living in the Amazon River Basin. Unfortunately, because of deforestation, the DNA of the last species the proton was a part of was irrevocably lost. The proton watched the disintegration of the delicate double helix around it, powerless to save it. The cell lost its shape as supplies stopped being brought to it, and the proton ended up in the charred ground beside the dead animal, the last representative of its species. Compared to all the transitions the proton has been through, from a supernova to an asteroid collision, this one disturbed it the most. By a strange turn of events more complicated than the proton's travels for the past 10 billion years, it ended up in the ink used to print an issue of the SciTech, inside the period of the last sentence of this article.
Death?

Even a proton must die.
    If the universe is closed, and ends in a "Big Crunch," the universe will revert back to a state of pure energy and perhaps begin all over again, one in a long string of universes in which protons are formed. Or maybe our present universe is the only universe that contains protons, each successive universe formed by different building blocks. In that case, the proton of this universe would be a representative of a unique class of particles never to appear again.

    Of course, the universe may be open, its expansion slowing to an imperceptible crawl as time passes. In this case the proton will outlive all life existing in the universe, past the time when all the stars run out of fuel, blinking out one by one, and the universe grows black. In 1036 years the proton will decay into its component quarks as the universe evolves into state of pure energy, like its origin.